利用简化的充分统计量在分布式传感器网络中进行纯方位跟踪

本文介绍一种用于具有附加高斯噪声的一般非线性量测模型的分布式参数估计算法。我们证明:当扩展为多传感器情况得出一个线性融合规则时,由Kulhavy′提出的贝叶斯-闭式估计算法与局部的后验密度的形式无关。特别是Kulhavy′算法产生一组表示局部传感器密度的简化的充分统计量(RSS),这是在全局处理机中进行简单地相加和相减而获得最优融合。我们讨论了关于贝叶斯-闭式算法的各种近似值,得到非线性量测模型的实际参数估计器,并将这种近似技术应用于纯方位跟踪问题。把分布式跟踪器的性能与基于在修正的极坐标(MPC)中实现的广义卡尔曼滤波器(EKF)的另一种算法作了比较。已经证明:从通常的EKF意义上讲,贝叶斯-闭式估计器没有发散,因此在单向和双向发送方式中都可以利用贝叶斯-闭式技术。     

潜在故障状态可测的一种故障检查模型

从系统的功能故障状态和潜在故障状态两方面讨论了故障检查模型,基于延迟时间模型推导了系统的期望可用度模型并对其适用性进行了讨论与验证。     

Experimental and numerical investigations of interface properties of Ti6Al4V/CP-Ti/Copper composite plate prepared by explosive welding

Explosive welding technique is widely used in many industries. This technique is useful to weld different kinds of metal alloys that are not easily welded by any other welding methods. Interlayer plays an important role to improve the welding quality and control energy loss during the collision process. In this paper, the Ti6Al4V plate was welded with a copper plate in the presence of a commercially pure titanium interlayer. Microstructure details of welded composite plate were observed through optical and scanning electron microscope. Interlayer-base plate interface morphology showed a wavy structure with solid melted regions inside the vortices. Moreover, the energy dispersive spectroscopy analysis in the interlayer-base interface reveals that there are some identified regions of different kinds of chemical equilibrium phases of Cu–Ti, i.e. CuTi, Cu₂Ti, CuTi₂, Cu₄Ti, etc. To study the mechanical properties of composite plates, mechanical tests were conducted, including the tensile test, bending test, shear test and Vickers hardness test. Numerical simulation of explosive welding process was performed with coupled Smooth Particle Hydrodynamic method, Euler and Arbitrary Lagrangian-Eulerian method. The multi-physics process of explosive welding, including detonation, jetting and interface morphology, was observed with simulation. Moreover, simulated plastic strain, temperature and pressure profiles were analysed to understand the welding conditions. Simulated results show that the interlayer base plate interface was created due to the high plastic deformation and localized melting of the parent plates. At the collision point, both alloys behave like fluids, resulting in the formation of a wavy morphology with vortices, which is in good agreement with the experimental results.     

使用低分辨率雷达和神经网络进行舰船目标识别

本文研究使用低分辩率下靶区雷达包络线、预处理和神经网络工具进行舰船目标分类的方法。文中使用改进的傅里叶离散梅林变换来提取对雷达姿态角变化不太敏感的某些特征。使用Kohonen的学习矢量量化(LVQ)自组织映射对这些特征矢量进行分类。文中也研究了使用反向传播算法进行训练的前馈网络在目标分类中的应用,并将这一分类系统用于模拟和真实两种数据。对于目标姿态角误差不超过30度的真实数据,分类的正确率高达90％。     

小睡胜千金——美军重视作战中的睡眠因素

在伊拉克战争期间,人们常常可以看到这样的电视画面:背负沉重武器装备的美英联军通过沙漠和城镇向巴格达进军。为了赢得这场战争,美英联军士兵疲于奔命。战斗常常要持续数小时,而且经常在夜间,参战士兵很少有时间睡觉,只能在坚硬的地面上打个小盹。负责保障的士兵的日子也不好过——他们需要竭尽全力为一线部队提供补给和服务。他们面临的最大问题就是疲惫和睡眠。 为帮助人们理解和减轻睡眠匮乏对士兵身体和作战造成的不良影响,长期以来,美国陆军一直对疲劳睡眠问题进行细致而又广泛的研究。这是卡伦·弗菜明-迈克尔(Karen Fleming—Michael)在10月29日美国陆军新闻网作的报道。     

加快实施非公经济参与国防工业建设的战略

国内非公经济迅猛发展及其特殊优势．使其具备了参与国防科研生产的能力和条件，并正在成为国防工业的重要组成部分和国防现代建设的重要推动力量。目前一些非公企业在市场机制驱动下通过一些“历史渠道”、“跳窗户”或“开后门”已进入国防科研领域，但只是一股被边缘化的生产力，与它快速增长的发展规模和贡献很不相称，并且只局限在“技术参与”范畴，仅限于对某些产品和技术的补充，全面参与国防建设还存在观念、体制和机制等诸多障碍。 政府主管部门要转变观念和职能，加强对非公经济的公共服务和市场监管，建立和完善相应的政策法规、制度和程序，依法维护非公企业从事军品科研活动的正当权益。     

基于专利分析的智能引信安全控制技术

本文基于Patentics数据库提供的数据，通过对智能引信安全控制技术领域的国内外专利进行检索及统计分析，从专利申请量、申请区域、国际专利分类技术构成和重点研发团队等方面对智能引信安全控制技术的专利态势进行深入研究，并结合专利文献着重对重点研发团队的技术发展路线进行解读，进而为实现引信安全控制的智能化发展给出了意见和建议，如发展多功能小型化引信、高安全性自适应控制引信和高可靠性安全/毁伤协同智能引信等，以期为政府、企业及科研机构的决策提供参考，提高科技创新的起点。     

The Pervasive Role of Rank in the Health of U.S. Veterans

The following article tests the hypothesis that veterans have better health if they were officers when they were in the U.S. military than if they served in the enlisted ranks. It examines this hypothesis by presenting results from logistic regressions that are based on four surveys: the National Survey of Veterans, the Survey of Retired Military, the Panel Study of Income Dynamics, and the Wisconsin Longitudinal Study. In all four of these surveys, the evidence is consistent with the hypothesis that military rank is associated with health, particularly among veterans who served longer. It also suggests that the health gradient by rank is independent of similar gradients by education and income as well as health differences by race. These findings indicate that health may be influenced not just by differences in civilian society but also by those in the military.